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UNITED STATES PATENT OFFICE.

GEORGE B. TVALKER, OF LONDON, ENGLAND.

TREATMENT OF'YUCCA 0R SOTAL' r'iblzrt FOR THE PRODUCTION OF PAPER PULP 0R STOCK, AND OBTAlNlNG BY-PRODUCTS TH EREFROM.

SPBCIFICATIQN forming part of Letters Patent No. 310,753, dated January 13, 1885.

Application filed May 23, 1894. (So specimens.)

To all. whom it may concern:

Be it known that I, Graonon Boumnxc \VALKER, a citizen ofthe United States, residing at the city of London, England, have invented certain new and useful Improvements in the Treatment of the Yucca or Sotal Fiber for the Production of Paper Pulp or Stock, and in Obtaining By-Products therefrom, of which the following is a specification.

, My invention consists of certain improvementsinthetrcatment of the fiber ofthe Yucca draconis, or Yucca pubcrula, or Yucca brciifo- Zia, or Sotal tree, so as to produce a pulp or paperstock of a finer quality than heretofore, and, the agents employed being native products drawn from the immediate locality (California) where the fiber is grown, with increased economy. The yucca wood or plant, having been unbarked, shredded, or torn up, so as to be in the condition resembling, tow, by suitable and known machinery, in any suitable manner, is brought into tanks provided with perforated double bottoms; water containing common salt or waste solutions, resulting from a subsequent part of the process, is run onto the mass, so as to cover the mass, which is then weighted down and allowed to remain in contact with the same for several days; but if thc temperature is raised to about 100 Fahrenheit by means of steam this part 'of the process will be accelerated.

To facilitate the next operation, I prefer to pass the longer portions of fiber through a straw-chopper before the material is treated in the aforesaid tanks, so that the main portion 0.1" the fibcrundcr treat ment should not exceed one inch in length. The material is now removed from the tanks and brought under a system of trituration or further opening upof the fiber by means of a grinding ort iturating eontrivauce. This may consist ofa fiber-opencr (dqfibrcur) or a pan mill, consisting of broad grooved or ribbed granite runners working upon a grooved or ribbed bed-plate of granite or horizontal stones working under allow of water,with a discharge trough or spout provided with a. sieve for preventing fibers of a coarser nature from passing through than desired; or I allow the mass as it passes from under the stones to run onto a sortingunachine, such as is used in wood-pulp mills, or

pared from the native horas mineral or earth occurring in the locality where the yucca is indigenous. This may be done simplyin vats or tanks provided with stirrers or agitators and steam-coils with condensing contrivanoe, as is well known. The mass of fiberis steamed in contact withthe solution of borax, which should be about 12 lanm, for two or three hours. The horas-liquor is then drained 01f from the fiber, and sulphurous-acid gas or vapor introduced by means of perforated inletpipt-s or coils. the tanks or vessels being covered during this part of the process, and remaining covered for an hour, (more or less,) while the sulphurous gas is being thus introduced. The fumes from five parts (more or less) of sulphur to one hundred parts of dry fiber, by weight, will be snflicieut. \Vat-er is now run in sutlicient to fioatthetiber, and the stirrcrs are set in motion, so as to wash out the combinations formed and left secreted in the fiber. This may be done in about half an hour. The waste liquor thus obtained is, by preference, used as a steep-liquor for the first part of the proccss\'iz., the digestion in the tanks. The horas-liquor run off isthentreated for borax, the liquor being first filtered through a bed of animal charcoal to remove the coloringanattcnand afterward boiled down and crystallized in the ordinary way. By this means a cheap and valuable agent in the treatment of the fiber is secured, as I am refining the crude borax of the country at the same time that I am treating fiber.

In the production of sulphurons acid 1 cmploy the crude sulphur of the country, either in the form of native sulphur or of pyritcs, in the ordinary manner, with the precaution of passing the gas or fumes through awasher containing water to which sulphite of soda has been added, or milk oflime, so as to neutralize or eliminate any sulphuric acid which ICO may form. The sulphurous acid may also be made by fusing together the crude sulphur hereinbefofe mentioned and sulphate of iron in a retort, wheusulphide of iron will be formed and sulphurous acid given off. The sulphide of iron is used over again for the fresh formationof sulphate of iron, and so on continuously. I also form sulphurous acid by passing the fumes of burning sulphur or pyrites through a tower filled with vegetable charcoal, sawdust, pith from the yucca. or such like material arranged en the pri .n-iple of the scrubber of gas-works. The sulphurons acid thus absorbed in the before-mentioned material may be easily driven off for use from a retort, and may be employed without washing, if required.-

I wish it to beundeistood that I do not confine myself solely to the use of gaseous sulphurous acid, but also use itwhere found nec essary or convenient,,in a condensed or liquid form, inconneetion with other solutions.

For commoner descriptions of paper the borax solution may be dispensed with, and I use simply a digestion with snlphurous acid. by allowing the moist fiber to absorb a larger quantity of the acid gas than IDIQYSUDSF stated, or about equal to the gas to be evolved from ten parts (more or les of sulphur to one hundred parts, dry weight, of fiber under treatment, and steamed in the same for about four hours in a closed or covered vessel. The liquor'foruied is run off and used as a steeping solution. The fiber then washed in a warm weak solution of earoonate of soda.to prepare it for bleaching and for softening the fiber. This liquor may also be used in the steeping operation. In either case the mate rial is now ready for bleaching, which Illa) be efieeted 1n the ordinary manner, or by any known or convenient means; but I prefer for high-talus paper to bleach with hypochlorite of magnesia. instead of hypoehlorite of lime, the former being less injurious to the fiber, and imparting a brighter color.

I claim- 1. The method of preparing paper pulp or waste acid sulphite liquors, then opening the fiber, and then digesting it in a closed vessel by means of sulphnrons acid while being agitated, substantially as set forth.

2. The methodof preparing paper pulp or stock from yucca fiber, consisting in treating the fibenafler it has been rendered intoa condition of tow, ia the manner described, by steepingit in waste acid sul'phiteliqnors, then opening the fiber, and then digesting it; in a closed vessel by means of borax-liquor and sulphurons aeid while being agitated, and then washing in a weak carlmuate-of-soda solution, substantially as set forth.

3. 1n the method of preparing paper pulp or stool: from yucca fiber. the method of treating the fiber by means of a solution of crude or native bot-ax, in combination with sulphurous acid, substantially as set forth.

4. In the method of preparing paper pulp or stock from yueea fiber. the method of treati-ng the fiber by means of waste acid sulphite liquors from a previous operation, substantially as set forth.

London, April .29, 1884.

GEO. B. VALKER.

\Vitnesses:

W. J. Nonwoon, J. Wyn, Both of IT Graecehnrc'h 81., London, E. C. 

